Alumina powder has been used widely in industries as row materials for ceramic materials and the like, an abrasive compounds and fillers. As a process for the preparation of such alumina powder, a process of calcining an alumina precursor powder is known. As the alumina precursor powder, aluminum hydroxide powder obtained by hydrolysis of an aluminum alkoxide is used. A process of calcining the aluminum hydroxide powder is known wherein the powder which is charged in a calcination vessel such as a sagger case is calcined so as to prevent flying apart of the alumina precursor powder (see, for example, Reference 1 which is referred to below).
However, the aluminum hydroxide powder which is obtained by the hydrolysis of the aluminum alkoxide has a lower bulk density. Thus, the conventional process for the preparation of alumina powder wherein such aluminum hydroxide powder as a precursor is heated is not always an industrially advantageous process because of a low volumetric efficiency.    Patent Reference 1
JP H08-301616 A (paragraphs [0002] and [0003])